(a) Field of the Invention
The present invention relates to a sound device having the full-gamut single-body sound membrane, and more particularly to a single-body sound membrane structure in a speaker, wherein the sound membrane comprises multi-parts and each multi-part in the sound membrane structure is applied with material of different intensity, such that a full-gamut sounding requirement comprising high-frequency, mid-frequency, and low-frequency of audible range can be performed by a single-body sound membrane.
(b) Description of the Prior Art
As highly development of human economy, life quality is improved; along with that requirement of quality of leisure life is getting stringent. In all kinds of leisure activities, improvement of requirement in audio-visual activities, including watching TV programs, movies, or listening to music, relies on development of the audio-visual products. For the visual product, the development is changing with each passing day, and the product has been developed to a digital planar display with high resolution. No matter a liquid crystal display or a plasma TV set, the high resolution and low radiation product has been rapidly developed. On the contrary, there are few vendors who devote to the development for improvement and break-through of the audio product. The primary reason is that the structure of a speaker, which is a mainstream of the audio product, is simple and has been used for a long time, and hence is commonly recognized to have no space for the improvement. Although most of the research and development of existing audio products are focused on amplifying circuits, this concept of concentrating on details but forgetting the main objective is not correct from a viewpoint of the present inventor.
The speaker structure includes a sound membrane, and for the existing sound membrane, including a paper sound membrane, a recent aluminum sound membrane, plastic sound membrane, or a sound membrane made by any other material, locations where high-frequency, mid-frequency and low-frequency vibrations occur all reside in a single sound membrane of a same material, density, and intensity, which is provided with the following shortcomings:                1. In terms of characteristics, a characteristic curve is provided with a narrow range, a non-flat shape, and a large distortion, as shown in FIG. 1. Under a same magnetic circuit design, a peak-to-valley difference of the distortion is normally 10˜15 dB, and a bandwidth is narrower, which is about 20˜25% Hz. If a sound frequency is designed to be 10 KHz, then only 8 KHz can be achieved in reality, and for a design value of 20 KHz, only 10˜13 KHz can be achieved before the sound frequency starts to descend. Otherwise, a short-loop design should be implemented, a tweeter (H-CONE) should be employed, vibration mass should be decreased, structure and mass of a voice coil should be changed, a row width of a voice coil wire should be decreased, or a shape of the voice coil body should be modified, which will increase cost, and result in a false property that is not in compliance with an audio condition to create a false tone.        2. In terms of tone quality, in a same sound membrane, the uniform material cannot develop proper timbre of the high-pitched, mid-range, and low-pitched tones at a same time. A limitation of the conventional sound membrane made by the uniform material of the same structure design can be described by a principle of see-saw; if the low-pitched tone is emphasized, then the mid-range tone will be lost, which results in an obscure and non-clear sound, on the other hand, if the mid-range tone is emphasized, then the low-pitched tone will be lost relatively, which results in a sharp and unpleasant sound. Obviously, one takes one thing into consideration to the neglect of the other. Unfortunately, a break-though has not been available yet to this limitation by the vendors.        3. In terms of efficiency, as the material, structure, and density of the same sound membrane are consistent, the single-body sound membrane cannot radiantly manifest the timbre under all kind of amplitudes of the high-pitched, mid-range, and low-pitched tones; and it is easy to result in non-smooth manifestation of the timbre. Therefore, the efficiency of sound membrane cannot be developed, and it is unable to require the sound membrane to achieve the best performance of timbre.        
In order to manifest the perfect timbre of high-pitched, mid-range, and low-pitched tones without distortion, existing audio equipment can be deployed with a crossover which should be in collaboration with a separate tweeter, mid-range speaker, and woofer. The crossover can separate the high-pitched, mid-range, and low-pitched tones in music and fix the property and timbre, and then the sound can be sent out through the tweeter, mid-range speaker, and woofer of corresponding property, to acquire the manifestation of proper tone-quality.
Although each timbre of the high-pitched, mid-range, and low-pitched tone can be manifested by using the crossover in association with the separate tweeter, mid-range speaker, and woofer, the sound generated is not real and nature, and cost is high, by using the electronic crossover to fix and change the sound. Nevertheless, the world-wide audio technique has been limited by these flaws for a long time.